1996 Chevrolet Suburban "change aplug" Questions

I have an 89 G20 sports van with a 5.7 Fuel injected Changed the plugs recently....gaped them a .35...soon after the motor began skipping.....more of a hiccup at higher speeds and after it's warmed up

...heat? Is rad fan acting as I described? Let me know. 97 blazer heats up yo 260 then drops to 160, i changed the thermostat but still doing it, i also have heat then no heat there is aplug in the ...

...Unplug the temp sending unit and see if it goes to normal , if it does replace the sending unit. Will be aplug on or near the thermostat housing. If it does not change then most likely is a bad